Recuperator system for cannon



B. B. HOLMES. I RECUPERATOB SYSTEM FOR CANNON- APPLICATION FILED JUNE 1,1919.

1,413,534, Patented Apr. 18, 1922.

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B. B. HOLMES.

RECUPERATOB SYSTEM FOR CANNON- v APPLICATION FILED JUNE 7, I9I9- 7 1,413,534. at nted pr- 18, 1922.

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THE UNITED STATES ARMY.

REC'UPERATOR SYSTEIVL FOR CANNON.

1919. Serial No. 302,418.

(FILED UNDER THE ACT OF MARCH 3, 1883, 22 STAT. L, 625.)

To all whom it may concern:

Be it known that I, Bnnoronn B. HOLMES, or, Coast Artillery, UnitedStates Army, a citizen of the United States, stationed at Washington,District of Columbia, have invented an Improvement in RecuperatorSystems for Cannon, of'which the following is a specification.

The invention described herein may be used by the Government, or any ofits officers or employees in prosecution of work for the Government, orby any other person in the United States, without payment to me of anyroyalty thereon, in accordance with the act of March. 3, 1883.

This invention relates to improvements in a recuperator system forcannon and relates particularly to a single hydrdpneumatic mechanicalsystem which serves both as a brake to check the momentum of the gun inrecoil and as a means to place the gun back into battery incounter-recoil.

In present mechanism of this character, there are provided a recoilcylinder adapted to contain oiland a recuperator cylinder adapted tocontain oil on one side of a piston therein and air or a gas 'on theother side thereof. The oil portions of each of these cylinders areconnected by a port whereby pressure exerted upon the oil in the recoilb'ake cylinder, upon recoil of the gun, is transmitted to the oil in therecuperator cylinder which pressure acting upon its side of the pistontherein forces the same along the cylinder and compresses the air on theother side thereof, the said air thereby acting as a cushion in the saidrecoil movement and serving in its reactionv against the piston torestore the gun to battery. The port connecting the two cylinders is'usually'provided with a valve for controlling the flow of oil duringrecoil of the gun, This construction entails an enormous amount of workand expense in its manufacture since the air-oil recuperator cylindermustbe machined and polished to the finest degree to fit its piston veryaccurately and the piston must be polished in a like manner andspecially built-up to withstand the exceedingly high pressures involved.The construction is also objectionable in this, that the piston can notbe made tight enoughto entirely prevent leakage and thereby a mixture ofoil and air and a decrease of the air pressure.

It may be further stated that the oil-air pistonused in the present typeof recuperator must be made to; fit its cylinder so tightly that anenormous frictional resistance to its lineal movement is developed, apressure of several tons usually bein required to move the same. Thepresent inventron entirely overcomes this objection.

It 1s an object of the present invention to provide a mechanism whereinthe above enumerated objections, and other minor obectlons notenumerated, are entirely eliminated. To this end the construction of thepresent invention is very easy and cheap to manufacture, particularly inthis, that a 7 separate. collapsible air container or bellows isprovided to be placed within the recuperator cyhnder, such containerbeing of simple yet of very substantial character and cheap tomanufacture. This construction entirely eliminates the piston heretoforeused and the air cylinder heretofore entailing such heavy expense inmanufacture need now only be rough machined to provide a housing for theair bellows. This bellows is of sheet metal entirely closed in suchmanner that leakage of any air is impossible and the frictionalresistance therein is negligible since the bellows is entirely flexibleand has a smooth sliding fit within its cylinder.

While I have shown the invention as par ticularly adapted for use in therecoil mechanism of a gun, yet it is obvious that the constructionherein defined may be adapted to a variety of uses and therefore Idesire it understood that the invention is not limited to the particularart or combination Fig. 3 is a cross section taken on linemounted, thecradle being provided with guides 4: to receive the gun and the guides 5to receive the complemental guides 6 on the recoil mechanism 3. Thebreech lug 7 of the gun is secured to the recoil mechanism" The recoilmeche at 8 in the usual manner. anism consists broadly of the oil brakecylinder 9 and two air recuperator cylinders 10 with their operatingparts. While two recuperator cylinders are herein shown and described itshould beclearly understood that the invention contemplates either asingle cylinder or a plurality of cylinders. V

Referring more specifically to the recoil mechanism, 11 indicates theoil brake. piston provided with a piston rod '12secured to the cradlecap 13 by nut 14, the said rod passing through a gland 15 screwed intothe end of cylinder 9. 'By this construction the piston 11 is heldstationary with the cradle. Port 16 opening into the front end ofcylinder 9 and extending as at 17 and opening into the rear end or onerecuperator cylinder at 18, provides an oil communication therebetween.Adjacent to port 18, the two recuperator cylinders are connected by aport A separate collapsible air container or bellows 20 is mounted ineach recuperator cylinder 10. This bellows, except for the ends thereof,is of one-piece continuous resilient sheet metal normally extended asshown in F 2. The inner end thereof is closed by a separate pieceforming a piston 21. The outer end closure is in the form of a screwplug .22. The plugs 22 are each formed with a vent 23 connected by apipe 24 secured to the plugs by means of clamps 25. This connectionserves to provide a balanced or equal pressure in said bellows. Thedesired pressure maybe maintained by forcing air into the bellowsthrough the valve 26. The space 27 between thebellows and the innersurface of each recuperator cylinder 10 is normallvfilled with oil andsuch surface is longitudinally grooved at 28 to provide a passage forsaid oil upon the collapsing of the bellows.

As shown in Fig. 2, the inner end of the bellows extends short of theend of the cylinsection through such der thereby leaving a space 29. Bythis provision, the bellows is free to expand to always maintain a,balanced pressure between the oil in the cylinder and the air within thebellows. The oil being free to surround the entire exterior surface ofthe bellows, the pressure upon such surface is always equal to thepressure upon the inner surface thereof. Such construction prevents thebursting of the bellows. However to be doubly sure of preventing suchrupture of the bellows, a safety valve 30 is provided in the end 21thereof. As long as the pressure on either side of this valve isapproximately equal, the valve provides a complete closure but shouldthe bellows expand suiiiciently, owing to escape of oil, to allow thepiston 21 to reach the end of the cylinder, the bellows would beprevented from further expansion and the pressure therein becomeexcessive to the oil pressure in the cylinder, but before the excesspressure within the bellows could become great enough to rupture thesame, the valve -.would blow out and prevent such rupture.

It is often desirable and may be necessary in some guns, as where theforce of recoil is very great, to decrease the compressibility of thebellows without increasing or diminishing the length thereof or withoutchanging the oil pressure in the recuperator cylindeiy This may be doneby partly, filling the bellows with oil Or other liquid thereby usingamixture of'liquid and air or gas instead of the latter alone. A liquidbeing less compressible thana gas, the bellows with such a mixturetherein would be much more diflicult to compress.

Upon the recoil of the gun a vacuum is necessarily formed behind thepiston 11. a port 33 having a plug with a small hole 34 therein isprovided at this end of the oil cylinder to let a small quantity of airinto such vacuum chamber. This portion of air serves to cushion the gunupon the final movement of its return to battery.

The port 17, providing communication between the oil cylinder 9 andrecuperator cylinders 10, has a controlling valve 35 and a check valve36 therein. Both these valves operate automatically upon recoil of thegun. The valve 35 is normally open (when the gun is in battery) as shownin Fig.5. This valve is operated by means of an arm 37 thereon ridingwithin thegroove of an elongaged plate 38 secured to the cradle. Thisplate, as shown in Fig. 7, extends angularly to the cradle and uponrearward movement of the recoil mechanism the arm 37 is gradually movedto the right (Fig, 4) thereby closing the valve 35. The valve isnormally open when the gun is in battery and 'nearly closed at theextreme end of recoil. Bythis construction the gun is allowed to recoilquite freely upon the first shock of the explosion of the charge andsuch recoil is gradually checked along the entire path of recoil andfinally fully checked at the end of such path. It may be stated that theangular'positio-n of plate 38 may be varied or changed if desired tochange the lengthof recoil.'

The check valve 36 is normally held to its seat by means of spring 39.Upon the recoil of the gun, the oil forces the valve away from its seatagainst the action of the spring 39, thereby leaving free passage forthe oil to the recuperator cylinders. Upon counterrecoil and as the oilstarts to flow in the opposite direction, valve 36 closes and checks theflow of the oil which in such return must pass through holes to in thevalve. In this manner the gun is carefully and smoothly brought back tobattery.

The operation of the invention is as follows It should be clearlyunderstood that the cradle 1 is stationary and that the entire recoilmechanism 3 recoils with the gun. The piston 11 being secured to thecradle cap 13 is also held stationary. The gun is secured to the recoilmechanism as at Sand upon recoil carries such mechanism with it in thedirection of the arrow in Fig. 1. The oil cylinder 9 about rod 12, ports16 to 19 and the recuperator cylinders 10, outside of the bellows 20,are filled with oil under a pressure equal to the air pressure withinbellows 20.

Upon recoil, the oil cylinder 9 moves along piston 11 and forces oilthrough port 16, valves 35 and 36 (which is forced open by the oilpressure), ports 17, 18 and 19 into therecuperator cylinders 10. Thisoil pressure acting against pistons 21 compresses the bellows within therecuperator cylinders,

V the oil. around the bellows being allowed to pass freely along grooves28. At the beginning of recoil, the valve 35 is wide open but as therecoil mechanism moves rearwardly the valve arm 37 riding in the grooveof plate 38 thereby gradually closes the valve, the valve being nearlyfully closed at the end of recoilf Upon counter-recoil, the air withinthe bellows 20, being compressed, tends to expand the bellows and drivethe oil in the opposite direction. The check valve 36 is immediatelyseated by means of spring 39 and the oil pressure, the controlling valve35 being opened as the gun moves to battery. Since the oil must passthrough holes 40 in returning to the oil cylinder 9, the return of thegun to battery is gradual and smooth. The small portion of air drawn inthrough port 34 aids in cushioning the final movement of the gun tobattery.

From the above description it is evident that the present invention is areal advance.

in the art defined and provides a mechanism wherein the objects referredto are completely secured.

Having described'my invention what I claim and desire to secure byLetters Patent, is

1. In a cushioning device of the classdescribed, a brake cylinder andbrake piston therefor, a recuperator cylinder, a flexible bellowsfloatingly mounted in the recuperator cylinder and containing fluids, apiston head at one end of the bellows, a screw plug adapted to screwinto the recuperator cylinder for closing the other end of the bellows,means to permit the flow of fluid from one side of said piston head tothe other upon collapsing movement of the bellows, a passage wayconnecting said cylinders and a valve for gradually closing said passageduring the recoil of the gun.

2. In a cushioning device of the class described, a brake cylinder and abrake piston therefor, a recuperator cylinder, a flexible bellowsfloatingly mounted in the recuperator cylinder and containing fluid, apiston head at one end of the bellows, a closure for the other end ofthe bellows adapted to secure the bellows to the recuperator cylinder,means to permit the flow of fluid from one side of said piston head tothe other upon collapsing movement of the bellows, a passage wayconnecting said cylinders and a valve for gradually closing said passageduring the recoil of the gun.

3. In a cushioning device of the class described, a brake cylinder andbrake piston therefor, a recuperator cylinder, a flexible bellowsfloatingly mounted in the recuperator cylinder and containing a gas, apiston head at one end of the bellows, a screw plug adapted to screwinto the recuperator cylinder for closin the other end of the bellows,the inner sur aces of the recuperator cylinder being groovedlongitudinally to permit the flow of liquid from one side of saidpiston-head to the other upon collapsing movement of the bellows, apassage-way connecting said cylinders and a valve for gradually closingsaid passage during the recoil of the gun.

4. In a recoil mechanism, the combination of a brake cylinder and brakepiston therefor, a plurality of recuperator cylinders each having aflexible bellows'therein containing a fluid adapted to be compressed, apistonhead secured to one end of the bellows, a passage-way connectingthe brake cylinder with said recuperator cylinders, a liquid containedin the brake cylinder in front of the piston for filling said brakecylinder, the passage-way and the space in the recuperator cylinders inthe rear of said piston head and around the flexible sides of saidbellows whereby the fluid contained within the bellows is maintainedunder pressure; and a safety valve secured to said piston head forpermitting the escape of fluid should the pressure within the bellowsexceed the pres sure on the exterior thereof.

5. In a recoil 1neehanism,xthe combination ofan oil brake a plurality ofrecuperate! cylinders each havinga flexible bellows containing a gasunder pressure, screw-plugs for closing the forward ends of said bellowsadapted to sorewinto the recuperator cylinders, ports formed throughsaid plugs, a 10 pipe connecting said ports and a valve in said pipewhereby the gas supply of said bellows may be replenished.

BRADFORD B. HOLMES.

